How to save a webpage as one page long PDF

I'm using Acrobat Pro DC and want to save a web page as a one page long PDF. I've tried in both Firefox and Safari as well as from within Acrobat. None of the PDFs I created are a true representation of the webpages I want to save. I was able to do this a year ago and have completely forgotten how the heck I did it. I found an old tip from Karl Heinz Kremer of "PDF Acrobatics Without a Net" but the instructions do not work for either of the browsers I'm using. Hope someone can help!